Fodor's Expert Review Zion–Mount Carmel Highway and Tunnels
Two narrow tunnels as old as the park itself lie between the east entrance and Zion Canyon on this breathtaking 12-mile stretch of Highway 9. One was once the longest man-made tunnel in the world. As you travel the (1.1-mile) passage through solid rock, five arched portals along one side provide fleeting glimpses of cliffs and canyons. When you emerge you'll find that the landscape has changed dramatically. Large vehicles require traffic control and a $15 permit, available at the park entrance, and have restricted hours of travel. This includes nearly all RVs, trailers, dual-wheel trucks, and campers. The Canyon Overlook Trail starts from a parking area between the tunnels.